Tag: Gamma-ray burst

A long time ago in a galaxy far, far away…

NASA’s Chandra X-ray Observatory has detected a mysterious explosion in deep space and, although astronomers have some suspected causes for the incredibly powerful event, there’s a possibility that it could be something we’ve never witnessed before.

The signal is the deepest X-ray source ever recorded and it appears to be related to a galaxy located approximately 10.7 billion light-years away (it therefore happened 10.7 billion years ago, when the universe was only three billion years old). Over the course of only a few minutes in October 2014, this event produced a thousand times more energy than all the stars in its galaxy. Before that time, there were no X-rays originating from this location and there’s been nothing since.

The explosion occurred in a region of sky called the Chandra Deep Field-South (CDF-S) — the event was therefore designated “CDF-S XT1” — and archived observations of that part of the sky by the NASA/ESA Hubble Space Telescope and NASA’s Spitzer space telescope revealed that it originated from within a faint, small galaxy.

“Ever since discovering this source, we’ve been struggling to understand its origin,” said Franz Bauer of the Pontifical Catholic University of Chile in Santiago, Chile, in a statement. “It’s like we have a jigsaw puzzle but we don’t have all of the pieces.”

One possibility is that we could be looking at the effects of a huge stellar explosion, known as a gamma-ray burst (GRB). GRBs are caused when a massive star implodes and blasts powerful gamma-rays as intense beams from its poles — think super-sized supernova on acid. They can also be caused by cataclysmic collisions between two neutron stars or a neutron star and black holes. Should one of those beams be directed at Earth, over 10.7 billion light-years of travel, the gamma-ray radiation would have dispersed and arrived here at a lower, X-ray energy, possibly explaining CDF-S XT1.

Alternatively, the signal may have been caused by the rapid destruction of a white dwarf star falling into a black hole. Alas, none of these explanations fully fit the observation and it could, actually, be a new phenomenon.

“We may have observed a completely new type of cataclysmic event,” said Kevin Schawinski, of ETH Zurich in Switzerland. “Whatever it is, a lot more observations are needed to work out what we’re seeing.”

So, in short, watch this space.

The research will be published in the June edition of the journal Monthly Notices of the Royal Astronomical Society and is available online.

I’m not kidding, last week was a huge mess of a supernova doomsday circus. It was like whispering “there’s a bomb under your chair” to the person next to you in a crowded theater and then watching the resulting flood of people slam into the fire escape. It was internet chaos. And there was no stopping it.

I am of course talking about the first, great doomsday scare of 2010: T Pyxidis.

Luckily for me, the first headline I saw was in the UK’s Telegraph that read “Earth ‘to be wiped out’ by supernova explosion.” Uh oh, that title sounds rather definite. Immediately, the bullshit sensor in my brain was tripped so I stopped flicking through the embarrassing excuse for a UK newspaper and had a read.

According to the article, some star (that I can’t pronounce) was “set to self-destruct” (as a big hairy supernova), a little over 3,000 light years away. Global chaos will therefore ensue. The ozone layer will be stripped away… and the Earth will be “wiped out.” (I still can’t work out how the Earth will be “wiped out.”)

I’m only picking on the Telegraph.co.uk as my skepticism knives were already sharpened after a series of idiotic woo-fueled articles (here, here and here) the website has played host to in recent months, but they weren’t the only news outlet to go batshit crazy with the “WE’RE ALL GONNA DIE” angle.

But who was really to blame for this mess? After all, the media was just the messenger, they must have gotten their lead from somewhere. Ah yes, the scientists… what did those guys really say?

You can find out how I got to the bottom of the science behind the hype in my Discovery News article “Will Earth ‘Be Wiped Out’ by a Supernova?” but cutting to the chase, it turns out that the scientists may have been a little hasty in their attempt to make international headlines.

Sure, some of the numbers didn’t add up (mistakes happen), but issuing a press release with a huge wad of inaccurate doom wrapped inside is pretty irresponsible. Have a read for yourself:

An interesting, if a bit scary, speculative sidelight is that if a Type Ia supernova explosion occurs within [that distance] of Earth, then the gamma radiation emitted by the supernova would fry the Earth, dumping as much gamma radiation (~100,000 erg/square centimeter) into our planet [sic], which is equivalent to the gamma ray input of 1000 solar flares simultaneously. –Excerpt from the Villanova press release, “THE LONG OVERDUE RECURRENT NOVA T PYXIDIS: SOON TO BE A TYPE Ia SUPERNOVA?”

“…fry the Earth”? Come on, that’s not even an accurate scientific term about what would happen if we were hit by a surge of gamma-rays. What’s wrong with saying “…the Earth would be at the receiving end of a Death Ray”? If you’re going to do the job of the tabloid press, hyping up your own research before the tabloid press has even read the release, you may as well be accurate.

And speaking of accuracy, my colleague Ray Villard was at the AAS and confirmed that Sion’s numbers were out by a factor of 10. “A supernova would have to be 10 times closer [to Earth] to do the damage described,” Ray said.

Although I was tough on the Telegraph in my Discovery News article (let’s face it, with an inaccurate and inflammatory title like that, they had it coming), in this case I think the main issue lies with Sion and co.

Why over-hype your research to get attention, when the research was interesting enough without declaring doomsday? By me even writing about the subject again, I think I just answered my own question.

An artist impression of one of the most intensely magnetic phenomena in our known Universe, the magnetar (ESO/L. Calcada)

It was identified as a gamma-ray burst, resulting from a massive explosion in a distant, young galaxy. Then astronomers realised that this flaring object was much closer to home, in fact it was a gamma-ray source within the Milky Way. Astronomers detected 40 visible-light flashes, only for the source to vanish as quickly as it mysteriously appeared. So what generated this huge firework display for astronomers to originally mistaken it for a gamma-ray burst?